1. Field of the Invention
The present invention relates to patterning electromagnetic radiation and, more particularly, to microlens lithography and methods thereof.
2. Description of the Related Art
Lithography may be used to generate a pattern on a surface, such as a semiconductor wafer. A repeating pattern may be generated by projecting an image through an array of microlenses. For example, ultraviolet photolithography can include any of the following: contact photolithography, proximity photolithography and projection lithography; each typically uses chromium masks. Other techniques that can be used in microlithography include, for example, electron-beam writing, ion-beam lithography and laser pattern writing.
Microlens arrays, photolithography and methods of fabrication and uses have been described by, for example, Popovic et al., in U.S. Pat. No. 4,689,291, Tsumori in U.S. Pat. No. 5,324,623, Hamada in U.S. Pat. No. 5,453,876, Robello et al. in U.S. Pat. No. 5,723,264, Goto et al. in U.S. Pat. No. 5,774, 240, Burger in U.S. Pat. Nos. 5,973,844 and 6,124,974, Cullman et al. in U.S. Pat. No. 6,016,185, Johnson in U.S. Pat. No. 6,133,986, Kock et al. in U.S. Pat. No. 6,195,201 B1, and Nuytkens et al. in U.S. Pat. No. 6,200,709 B1.
Microlens lithography has been described by Völkel et al. in “Microlens Lithography: A new approach for large display fabrication,” Microelectronic Engineering, v. 30, pp. 107–110 (1996), in “Microlens array imaging systems for photolithography,” Opt. Eng., v. 35(11), pp. 3323–3330 (November 1996), and in “Microlens Lithography and Smart Masks,” v. 30, pp. 513–516 (1997). They have also been described by Nussbaum et al. in “Design, fabrication and testing of microlens arrays for sensors and Microsystems,” Pure Appl. Opt., v. 6, pp. 617–636 (1997) and by Dändliker et al. in “Non-conventional techniques for optical lithography,” Microelectronic Eng., v. 27, pp. 205–211(1995).
Microlens lithography-related techniques have been described by Ida et al. in “LETI's FED patterning technique,” European Semiconductor, pp. 97–99 (April 1997) and in “12.3: New Microlithography Technique for Large Size Field Emission Displays,” Euro Display, pp. 177–180 (1996), by H. Smith in “A proposal for maskless, zone-plate-array lithography,” J. Vac. Sci. Technol. B14(6), pp. 4318–4322 (November/December 1996), and by Djomehri et al. in “Zone-plate-array lithography in the deep ultraviolet,” J. Vac. Sci. Technol., B16(6), pp. 3426–3429 (November/December 1998).